Alex Weldon: This seems to prevent Black from encroaching any further, and I don't see any way to accomplish that in sente. My concern, however, is what happens if Black plays at
. If White cuts Black off, could Black then live in the corner?
This pretty much boils down to variations of the L-group. I'm sure Black can't live.
If in the previous diagram at
here, then
and
.
and
are miai. For the record, the explanation why Black dies is given at Rectangular six in the corner.